Nucleoside sugar esters of sulfamic acid and method for preparation of the same

ABSTRACT

Novel nucleoside sugar esters of sulfamic acid having the formula   WHERE R is selected from the group consisting of hydrogen and hydroxyl and B is a nucleic acid base selected from the group consisting of adenine, hypoxanthine, guanine, cystosine, uracil, and thymine and a method for preparing the esters. The esters are useful as antibacterial, antitrypanosamal, and, in vitro anticancer agents.

United States Patent [72] Inventors [21 1 Appl. No. [22] Filed [45] Patented [73] Assignee [54] NUCLEOSIDE SUGAR ESTERS 0F SULFAMIC ACID AND METHOD FOR PREPARATION OF THE SAME 6 Claims, No Drawings 52 us. Cl. zoo/2115a. 424/180 [51] Int. Cl ..C07d 51/52, C07d 51/54 [50] Field of Search 260/2115, 543 R, 457, 234

[56] References Cited UNITED STATES PATENTS 3,017,407 H1962 Petracek et al. 260/234 3,057,855 10/1962 Smith et a] 260/234 Primary Examiner-Lewis Gotts Assistant Examiner.lohnnie R. Brown Attorney-C. Harvey Gold ABSTRACT: Novel nucleoside sugar esters of sulfamic acid having the formula where R is selected from the group consisting of hydrogen and hydroxyl and B is a nucleic acid base selected from the group consisting of adenine, hypoxanthine. guanine, cystosine, uracil, and thymine and a method for preparing the esters. The esters are useful as antibacterial. antitrypanosamal, and, in vitro anticancer agents.

NUCLEOSIDE SUGAR ESTERS F SULFAMIC ACID AND METHOD FOR PREPARATION OF THE SAME The invention described herein was made in the course of work under a grant or award from the Department of Health,

Education and Welfare.

BACKGROUND OF THE INVENTION Nucleocidin is a potent antitrypanosomal antibiotic that occurs naturally in nature. The chemical structure of this compound is thought to be l is} OH OH (1) The compound is particularly active against the organisms causing certain types of sleeping sickness, e.g., in Africa-the sleeping disease organism is known as Trypanosoma rhodesiense and in South America the disease organism is known as Trypanasoma cruzi. The seriousness of the sleeping sickness disease is demonstrated by the'fact, that, for example, in the" country of Brazil approximately 28 percent of the male population die of the disease. Sulfamate esters such as nucleocidin with an unsubstituted nitrogen are rare andnucleocidin is the only known antibiotic containing the sulfamate ester group. In addition, this compound is one of the'veryfew'naturally occurring fluoro compounds. Applicants have prepared new synthetic sulfamate esters of nucleosides that-are substantial structural models of nucleocidin shownto be useful as antibacterial, antitrypanosamal, and anticancer agents'in-that they exhibit a pronounced inhibition of Streplococcusfaecalis and Trypanosoma rhodesiense.

SUMMARY OF THE INVENTION In its broadest form the invention relates to nucleoside sugar esters of sulfamic acid having the formula 0 mN-ii-o-on, O B A N l where R is selected from the group consisting of hydrogen and hydroxyl and B is a nucleic'acid base selected-from the group consisting of adenine, hypoxanthine, guanine, cytosine, uracil, and thymine.

In another embodiment of the invention "the nucleoside sugar ester of sulfamic acid has the formula Still another embodiment of the invention relates to a method for preparing the nucleoside sugar esters of the type herein set forth,

DESCRIPTION OF THE PREFERRED EMBODIMENT Nucleoside sugar esters of sulfamic acid having the general formula 0 mN-ii-o-om where B is a nucleic acid base selected from the group'consisting of adenine, hypoxanthine, guanine, cytosine, uracil, and thymine are synthesizedby reacting a nucleoside such as adenosine, inosine, cytidine, uridine, etc., having the general formula where B is selected'from the groupconsisting of adenine, hypoxanthine; guanine, cyt0sine,'uracil, and'thymine with either'an ortho ester such as triethyl o'rthoformate, trimethyl orthoformate, triethyl orthoacetate, trimethyl orthoacetate, trimethyl orthobenzoate, triethyl orthobenzoate, etc.; an aldehyde such as acetaldehyde, benzaldehyde, p-(N,N- dimethyl)-benzaldehyde p-methoxybenzaldehyde, etc.; or a ketone such as acetone, cyclopentanone. cyclohexanone diethyl ketone, etc., in the presence of an'acidic catalyst, i.e.,'

any acid,-such as formic acid, acetic acid, hydrochloric acid, sulfuric-acid, etc. to block-the'2' and 3' hydroxyl groups of the nucleoside and produce acompound'having' the general formula such as sulfamoyl chloride, N-methylsulfamoyl-chloride, N-

ethyl :sulfamoyl chloride, N-ethoxy carbonylsulfamoylchloride, N-(N 'propyl) aminocarbonylsulfamoylchloride, N-(S me'thyl) 'carbonylsulfamoylchloride, etc., or alternatively the blocked nucleoside isreactedwith sulfamoyl chloride'inthe: presence of'an acid accepting'base such as pyridine, triethylamine,-4 A; molecular sieves, etc., in an aproticsolvent, to produce the blocked'nucleoside sulfamic acid ester having thegeneral formula rolou The 2' and 3' hydroxyl groups of the nucleoside are then deblocked to produce the desired sugar ester by reacting the .nucleoside with an acidic catalyst of the type heretofore described in a protic solvent such as water,'alcohols', mixtures of water and alcohol, etc. The concentration of the acidic catalyst is maintained at a level sufficient to deblock the molecule but sufficiently dilute so that the molecule is not destroyed and the sulfamic acid ester is not solvolyzed. The desired concentration can be insured by following the reaction, according to the established practice with thin layer chromatography (tlc).

If blocking of the 2' and 3' hydroxyl groups was accomplished through the use of an ortho ester the resulting product is then finally treated with a deblocking base such as am 'monia, sodium hydroxide, ion exchange resins such as the -resin known by the trademark Amberlite lR-45, sodium carbonate, etc. It is to be noted the base is used at a concentration sufficient to solvolyze the residual blocking group without solvolyzing the sulfamic acid ester of the nucleoside. This conflentration can also be ensured by following the reaction with Nucleoside sugar esters of sulfamic acid having a general formula where B is selected from the group herein enumerated are synthesized by reacting a nucleoside such as 2-deoxyadenosine, 2'-deoxycytidine, thymidine, 2'-deoxyinosine, etc., having the general formula thereby producing a compound with the blocking group selectively joined to the nucleosides primary alcohol position and having the general structural formula Xr-O-CH;

where X, is the blocking group. The resulting blocked compound is then reacted with the ionizing base and subsequently with the sulfamoylchloride in the aprotic solvent or altematively with the acid-accepting base and the sulfamoyl chloride in the aprotic solvent to produce a sulfamated nucleoside having the general formula The sulfamated compound is then deblocked with the acidic catalyst in the protic solvent to produce the desired nucleoside sugar ester of sulfamic acid.

Nucleoside sugar esters of sulfamic acid having a general formula resulting product is then reacted with a 3' hydroxyl blocking agent such as acetic 'anhydride, benzoyl chloride, p-toluyl chloride, etc., to produce a compound having the general structural formula (13) H o-x,n H

Where X, is the blocking function bonded to the oxygen of the B'hydroxyl group. This compound is then reacted with the acidic catalyst in the protic solvent and the product is reacted with the ionizing base in the aprotic solvent and sulfamated by reaction with the sulfamoyl chloride or alternatively with the acid-accepting base and the sulfamoyl chloride in the aprotic solvent. Finally, as heretofore described, the resulting sulfamate product is deblocked by reaction with the d'eblocking base in the protic solvent to produce the desired compound.

The nucleoside sugar esters of this invention are useful antibacterial agents which inhibit the growth of organisms such as Streptococcus fae calis and Escherichia coli when added as an aqueous solution to a logrithmatically multiplying aqueous culture of the organism. They also have marked inhibitory activity against Trypanosama rhodesiense in mice, when given to mice previously infected with the organism, and show in vitro inhibitory activity against certain cancer cell lines which are used for animal screening by the-National Institutes of Health, Cancer Chemotherapy National Service Center when the compound is added as an aqueous solution to tumor cells in aqueous suspension.

The following examples will illustrate the practice of the invention and serve to demonstrate the results obtainable thereby:

EXAMPLEI Preparation of 5'-O-sulfamoyladenosine. 3l.7 mmol. of NaH was mixed into a suspension of mmol. mmol of 2'3'-O- ethoxymethylideneadenosine in 140 ml. of LZ-dimethoxyethane. The resulting suspension was stirred at room temperature for 2 hours whereupon it was cooled to 4 c. 30.0 mmol. of sulfamoyl chloride in 25 ml. of LZ-dimethoxyethane was added dropwise to the cooled suspension over a 15- minute period and the resulting mixture was stirred at 4 C. for 20 hours. 10 ml. of absolute ethyl alcohol was then added to the mixture whereupon the mixture was evaporated to dryness under reduced pressure at a temperature less than 40 C. 250 ml. of methyl alcohol was then added to the product and the resulting suspension was filtered and again evaporated to dryness under reduced pressure. The resulting product was mixed with 50 g. of silicic acid and l00 ml. of ethyl acetate and the mixture was once again evaporated to dryness under reduced pressure. 50 ml. of ethyl acetate was then added and removed under reduced pressure and this step was repeated two times. The resulting powder was added to a column containing 90 g.

of silica gel and it was washed with 1.3 liters chloroform and 1.0 liters of a 1:1 mixture of chlorofomi and ethyl acetate and finally eluted with ethyl acetate to remove 2,3'-O-ethoxymethylidene -5'-O-sulfamoyladenosine. The appropriate fractions as determined by tlc were combined and evaporated under reduced pressure to yield a white foam. This foam was stirred at room temperature in 100 ml. of 5 percent formic acid for 18 hours, filtered and then neutralized to a pH of 7.5v with concentrated Nl-LOH. The resulting solution was then cooled at 4 C. for 40 hours whereupon it was filtered and washed with cold water. The precipitate was dissolved in 150 ml. of 0.06 N HCl and the solution was neutralized to a pH of 7 with concentrated Nl-LOH and cooled to 4 C. for 2 days to form a precipitate that was filtered, washed with cold water and dried over P P, at 70 C. and 0.01 mm. Hg for 3 days. The

resulting 2.0 g. of solid was shown by'elemental analysis and a nuclear magnetic resonance spectroscopy to be 5'-O- sulfamoyladenosine.

EXAMPLE 11 Preparation of 5'-O-sulfamoylinosine. 20 mmol. Nal-l was added to a solution of 8.7 mmol. 2' 3-o-rnethoxymethylideneinosine in 70 ml. 1,2-dimethoxyethane and the resulting suspension was stirred for 3 hours. Thereafter, the suspension was cooled in an ice bath and 17 mmol. sulfamoyl chloride in 50 ml. l,2'dimethoxyethane was slowly added to thesuspension. The resulting mixture was then stirred at 4 C. for 48 hours whereupon 2 ml. of concentrated Nl-LOH was added and the product was evaporated to dryness under reduced. pressure at a temperature of less than 30 C. The product was then partitioned between ethyl acetate and water and the organic layer was evaporated under reduced pressure. The resulting solid was dissolved in 100 ml. of 5 percent aqueous formic acid and the acid solution was stirred for 24 hours and evaporated under reduced pressure to give a solid. 50 ml. of methyl alcohol was added to the solid and the solution was stirred with 20 ml. of Amberlite IR-45 ion exchange resin for hours. The solution was filtered and the filtrate was, evaporated under reduced pressure. 70 ml. of water was then added to the product and the aqueous layer was extracted with chloroform. A mixture of methyl alcohol and ethyl alcohol was added to the product whereupon it was removed by evaporation and 1.94 g. of a white solid resulted which was shown by tlc to be 5 -O-sulfamoylinosine.

EXAMPLE Ill Preparation of 5'-O-sulfamoyl-2'-deoxyadenosine. 0.25 g. Nal-l was added to 0.84 g. of 30-acetyl-2-deoxyadenosine in 200 ml. of 1,2-dimethoxyethane to form a suspension. After stirring the suspension for 0.5 hours it was cooled in an icebath whereupon 0.67 g. of sulfamoyl chloride in 10 ml. 1,2- dimethoxyethane was added dropwise and the mixture was maintained at 4 C. for 48 hours. Thereafter, 20 ml. of ethyl alcohol was added to the mixture and the solution was evaporated under reduced pressure to dryness. The resulting solid was triturated in ml. of cold 0.06 N HCl, filtered and neutralized to a pH of 6.5 with 1.0 N Nl-hOl-l. The resulting precipitate was cooled at 4 C. for 12 hours and was filtered and washed with cold water and then triturated with ethyl ether to give 0.78 g. of chromatographically pure 3'-O-acetyl 5'-Osulfamoyladenosine. This product was then mixed with 10 ml. of methyl alcohol presaturated with Nl l at -10 C. whereupon the resulting solution was sealed in a vessel and allowed to stand for 5 hours at room temperature. The solution was then evaporated to dryness, the resulting product was partitioned between water and chloroform, the aqueous layer was evaporated under reduced pressure, and the residue was dissolved in ethyl alcohol. This solution was then cooled and hours and then dried over P 0 at 24 C. and 0.01 mm. Hg for 3 hours. The dried solid was shown by elemental analysis to be 5'-O-sulfamoyl-2-deoxyadenosine monohydrate.

EXAMPLE IV Preparation of 3'-O-sulfamoyl-2-deoxyadenosine. 5.0 mmol. of Nal-l was added to a solution of 2.50 mmol. 5-O- trityl-20'-deoxyadenosine in 25 ml. of 1,2-dimethoxyethane and stirred for 0.5 hours. The resulting suspension was cooled in an ice-bath while 4.9 mmol. of sulfamoyl chloride in 15 ml. 1,2-dimethoxyethane was slowly added thereto and the resulting suspension was stirred at 4 C. for 24 hours. 20 ml. of ethyl alcohol was then added to the suspension and the volitiles were removed under reduced pressure. The resulting syrup was partitioned between ethyl acetate and water and the ethyl acetate layer was twice washed with water. The organic layer was then dried over NA SO filtered, and evaporated under reduced pressure to a foam. Thereafter, the foam was dissolved in chloroform and added to 25 g. of silica gel in a 3 X 15 cm. column. The chloroform was evaporated and the column was washed with 200 ml. chloroform and then eluted with ethyl acetate to remove 5'-O-trityl-3-o-sulfamoyl-2-deoxyadenosine as the product. The product was then mixed with 60 ml. of percent acetic acid and the resulting solution was heated rapidly in an oil bath to 93 C. and maintained at this temperature for 10 minutes. The solution was then rapidly cooled and evaporated under reduced pressure. 60 ml. of water was then added and the solution was extracted three times with 40 ml. ethyl acetate. Thereafter the aqueous layer of the solution was evaporated under reduced pressure and 50 ml. of ethyl alcohol was added, the solution was then evaporated to dryness under reduced pressure. 20 g. of silica gel and 80 ml. of methyl alcohol were then added to the product the solvent was again evaporated to dryness. The resulting powder was added to 220 g. of silica gel in a column and it was developed with 3 liters of a 98:2 ratio of ethylacetate and ethyl alcohol to remove 3'-O-sulfamoyl-2'- deoxyadenosine as the product.

EXAMPLE V Preparation of 5'-O-sulfamoylthymidine. 0.70 g. of sulfamoyl chloride was added to a mixture of 0.87 g. of 3'-O- acetylthymidine in 50 ml. of 1,2-dimethyoxyethane and 1 g. of 4 A. molecular sieves. The mixture was stirred at room temperature for 12 hours and then an additional 0.70 g. of sulfamoyl chloride was added. 10 ml. of absolute ethyl alcohol was then added and the solution was evaporated under reduced pressure. To the resulting semisolid was added 400 ml. of methyl alcohol and the slurry thus produced was filtered and the filtrate was evaporated under reduced pressure to a semisolid product. Crystallization of the product with about 15 ml. methyl alcohol yielded 0.94 g. of 5'-O-sulfamoyl-3'-O- acetylthymidine. This product'was then mixed with 70 ml. methyl alcohol presaturated with Nl-l at 10 C. The resulting solution was then sealed in a vessel and allowed to stand for 5 hours at room temperature. Then the solution was evaporated to dryness and dissolved in methyl alcohol and placed on a silica gel column. An air stream was passed through the column until it was dry whereupon the column was developed with 250 ml. of chlorofon'n and then a :5 ratio of a mixture of chloroform and methyl alcohol to remove the product 5'-O- sulfamoylthymidine.

EXAMPLE Vl Preparation of 3'-O-sulfamoyl-2'-deoxycytidine. 20 mmol. of NaH was added to a solution of 10 mmol. 5'-0-trityl-2'- deoxycytidine in 140 ml. of 1,2-dimethoxyethane and the resulting suspension was stirred for 1 hour. The suspension was then cooled with an ice-bath and a solution of 20 mmol. sulfamoyl chloride in 20 ml. of l,2-dimethoxyethane was added thereto. The volatiles were removed by evaporation under reduced pressure and 1 liter of ethyl acetate was added. The ethyl acetate was extracted with saturated NaI-ICO and then with water. The organic layer was dried over Na,so, and evaporated under reduced pressure to 5.0 g. of a foam. 3.4 g. of the foam dissolved in ethyl acetate was then added to a column containing 130 g. of silica gel. The column was then dried and was washed with 2 liters of ethyl acetate and 1 liter of a 95:5 mixture of ethyl acetate and methyl alcohol and finally a 90:10 mixture of ethyl acetate and methyl alcohol. The resulting product, 3'-Osulfamoyl -5-O-trityl2'-deoxycytidine, was recrystallized from a solution of methyl alcohol and ethyl alcohol and dried for 48 hours over P 0, at 75 C. and 0.01 mm. B3. 1.0 mmol. of the product was then added to l5 ml. of 80 percent aqueous acetic acid at 95 C. and the resulting solution was stirred for 15 minutes and then gradually cooled. The volatiles were removed by the addition of ethyl alcohol and evaporation under reduced pressure. Thereafter the resulting semisolid was partitioned between ethyl acetate and water. The organic layer was extracted several times with water and the combined aqueous layer was dissolved in a minimum volume of methyl alcohol and added I to a silica gel column. The column was dried and developed with a 5:95 mixture of methyl alcohol and chloroform. The appropriate fractions, as determined by tlc were pooled and evaporated under reduced pressure. The resulting solid was recrystallized from ethyl alcohol and was dried over P Elemental analysis proved the solid to be 3'-O-sulfamoyl-2'-deoxycytidine.

EXAMPLE VII An aqueous growth suspension of Escherichia coli bacterial organism was inoculated with a 3 l0"" molar aqueous solution of 5-0-sulfamoyladenosine and the growth of the bacterial organism was inhibited by 50 percent.

EXAMPLE VIII An aqueous growth suspension of Escherichia coli bacterial organism was inoculated with a 2 l0""" molar aqueous solution of 5'-O-suIfamoyl-2'-deoxyodenosine and the growth of the bacterial organism was inhibited by 50 percent.

EXAMPLE IX An aqueous growth suspension of Escherichia coli bacterial organism was inoculated with a ZXIO' molar aqueous solution of 3'-O-sulfamoyl-2+-deoxyadenosine and the growth of the bacterial organism was inhibited by 50 percent.

EXAMPLEX An aqueous growth suspension of Streptococcus faecalis;

EXAMPLE fill An aqueous growth suspension of Streplococcusfaecalis organism was inoculated with a 9X 1 0" molar aqueous solution of the compound of example IX and the growth of the bacteri- 5 al organism was inhibited by 50 percent.

EXAMPLE XIII A 4X 10 molar aqueous solution of the compound of ex- 10 ample VII was added to an aqueous suspension of Ehrlich ascites cancer cells and growth of the cells was inhibited by 50 percent.

EXAMPLE XIV A 4Xl0'"" molar aqueous solution of the compound of example VII was added to an aqueous suspension of Leukemia L-l 210 cancer cells and the growth of the cells was inhibited by percent.

EXAMPLE XV A 10 9 molar concentration of 5'-o-sulfamoyladenosine 2 exhibited pronounced in vitro inhibition of Trypanosoma wherein R is selected from the group consisting of hydrogen and hydroxyl and B is a nucleic acid base selected from the group consisting of adenine, hypoxanthine, guanine, cytosine. uracil, and thymine.

2. The nucleoside sugar ester of claim 1 wherein B is the nucleic acid base adenine and R is a hydroxyl group.

5 3. The nucleoside sugar ester of claim 1 wherein B is the nucleic acid base adenine and R is hydrogen.

4. A nucleoside sugar ester of sulfamic acid having the forbacterial organism was inoculated with a 4 l0'" molar aqueous solution of the compound of example VII and the growth of the bacterial organism was inhibited by 50 percent.

EXAMPLE XI An aqueous growth suspension of Streptococcus faecalis organism was inoculated with a 2Xl0' molar aqueous solution of the compound of example VIII and the growth of the bac' terial organism was inhibited by 50 percent.

wherein B is a nucleic acid base selected from the group consisting of adenine, hypoxanthine, guanine, cytosine, uracil, 7 and thymine.

5. The nucleoside sugar ester of claim 4 wherein B is the nucleic acid base adenine.

6. The nucleoside sugar ester of claim 4 wherein B is the nucleic acid base cytosine.

t I I? 1 l 

2. The nucleoside sugar ester of claim 1 wherein B is the nucleic acid base adenine and R is a hydroxyl group.
 3. The nucleoside sugar ester of claim 1 wherein B is the nucleic acid base adenine and R is hydrogen.
 4. A nucleoside sugar ester of sulfamic acid having the formula:
 5. The nucleoside sugar ester of claim 4 wherein B is the nucleic acid base adenine.
 6. The nucleoside sugar ester of claim 4 wherein B is the nucleic acid base cytosine. 